Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2004
Publication Date: September 30, 2004
Repository URL: http://www.ars.usda.gov/sp2UserFiles/Place/36221500/cswq-0004-143496.pdf
Citation: Sudduth, K.A., Hummel, J.W., Drummond, S.T. 2004. Comparison of the Veris Profiler 3000 to an ASAE-standard penetrometer. Applied Engineering in Agriculture. 20(5):535-541. Interpretive Summary: Precision agriculture is a crop management strategy which seeks to address within-field variability. An important component of precision agriculture is collecting data to map soil physical conditions within a field. One such physical condition, soil compaction caused by wheel traffic or tillage operations, is traditionally measured with the cone penetrometer. Although penetrometer design and operating standards are published, some recent devices deviate from these standards in order to incorporate other sensors. Because of this, it is important to understand the differences between compaction measurements obtained with standard and nonstandard penetrometers. In this research, we compared data collected with two standard penetrometers and one non-standard penetrometer that also senses soil electrical conductivity (EC). We found that the larger the penetrometer cone, the less variability among measurements, meaning that fewer measurements would be required with larger cones. We also found that penetration resistance measured with the EC penetrometer was significantly different than that measured with a standard penetrometer, but that it was possible to convert between the two. The research will benefit other researchers by documenting the differences between data collected with the EC penetrometer and other, standard penetrometers that are currently in use. It will also benefit extension specialists and crop advisors, by allowing them to understand some of the benefits and limitations of these new devices that they may want to use in their programs.
Technical Abstract: Cone penetrometers, as standardized by ASAE, have been used for many years as the primary instrument for investigating and quantifying soil compaction. Recently, non-standard penetrometers have become commercially available. These instruments depart from the standard so they can simultaneously sense additional soil parameters (e.g., soil electrical conductivity, EC) in addition to cone index (CI). In this research, we compared data collected with an EC-sensing penetrometer to data collected with ASAE-standard large cone and small cone penetrometers. The EC-sensing penetrometer operated at a faster insertion speed and exhibited a non-standard cone geometry. Cone geometry had a significant effect when comparing the EC-sensing penetrometer to standard large and small cones. There was also a significant effect of cone size between the two standard cones. It was possible to develop CI-dependent transformation equations to convert data collected with one tip to correspond with data from another tip, but a large amount of scatter was present in the relationship. No significant effect of insertion speed was detected between the standard insertion speed of 30 mm/s and the EC-sensing penetrometer speed of 40 mm/s. The amount of scatter present in replicate CI data was inversely related to cone diameter, indicating that fewer measurements would be required to obtain a given level of precision with a larger cone.